Highly flexible machine tool

ABSTRACT

A machine tool ( 1 ) has at least one but preferably two machining units ( 13, 14 ), which are assigned to two workpiece receptacles ( 8, 9 ). The machining units ( 13, 14 ) are adjustable in three axes (X, Y, Z), and they can each reach both workpiece receptacles ( 8, 9 ). The machining units ( 13, 14 ) are oriented such that their work spindles ( 11, 12 ) are in a preferably right space angle to one another. As a result, they can be moved past one another without colliding. Moreover, they can also work on the same workpiece at the same time. The workpiece receptacles are positionable independently of one another about a preferably but not necessarily common pivot axis (S). The workpieces are also rotatable about an axis (V) perpendicular to the pivot axis. This arrangement enables flexible machining of the workpieces from arbitrary directions in space. Because each machining unit ( 13, 14 ) in principle can machine every side of the workpiece of every workpiece receptacle ( 8, 9 ), both machining units ( 13, 14  can be utilized evenly. This minimizes idle times and time losses.

FILED OF THE INVENTION

The invention relates to a machine tool, in particular for metal-cuttingmachining of workpieces.

BACKGROUND OF THE INVENTION

For machining workpieces of complex shape, which for their productionmust pass through a relatively large number of different metal-cuttingmachining processes, especially for mass-scale machining or productionof such workpieces, machine tools are often used that on the sameworkpiece successively perform different machining operations fromdifferent directions. One example of such a machine tool can be found inU.S. Pat. No. 5,452,502. The machine tool disclosed there is embodied asa circular indexing machine tool and has a cross-shaped workpiececarrier disposed inside a cage-like base frame. Workpiece receptacledevices are disposed on the side faces of the arms of the cross-shapedworkpiece carrier. While the workpiece carrier can be rotated andindexed about a vertical axis, the individual workpiece receptacles areeach rotatable about horizontal axes, which are disposed at a tangent toan imaginary circle. As the workpiece carriers index onward, theworkpieces successively pass through different work stations. Thesestations are defined by machining units, which are retained on the basicframe so as to be adjustable in multiple directions. Each machining unithas one work spindle, which is provided with a revolver head. Therevolver head is embodied as a crown type turret head. Its spindles aredriven jointly by the work spindle. By revolution of the revolver head,a desired tool can be transferred into a rectilinear lengtheningposition of the work spindle, thus putting it in the machining position.All the spindles of the revolver head are driven simultaneously, andthey continue to move even during the rotation or onward indexing of therevolver head.

With this circular increment machine tool, five-sided machining of theworkpieces is possible, which makes for high efficiency. However,oblique faces or oblique bores, that is, bores that do not form a rightangle with the axis of rotation (horizontal axis) of the workpiece,present a certain problem in machining. In special cases, in whichbecause of the workpiece design different machining times are needed inthe various work stations, it is also possible that the machining unitsof different work stations may work for variously long times. Theindexing time is determined by the longest machining time required.

SUMMARY OF THE INVENTION

With this as the point of departure, it is the object of the inventionto provide a remedy for this and to create a machine tool with which themost uninterrupted possible operation of individual work spindles andthus a high degree of utilization are attainable even if individualsides of the workpieces have to be machined for variously long times.

This object is attained according to one aspect of the invention thatmakes it. In its simplest structural form, the machine tool has amachining unit that serves two workpiece receptacles. Each workpiecereceptacle is embodied such that it can pivot the workpiece into atleast a mounting or removal position and into at least one definedposition but preferably a plurality of selectively definable workpositions. The pivot axis preferably passes crosswise through theworkpiece and in the ideal case through its center. Preferably, thepivot axis does not touch or intersect the workpiece fastening face butinstead extends parallel to it and spaced apart from it.

Both workpiece receptacles are disposed in the immediate vicinity of oneanother, and the machining unit can be moved by means of the guiding andadjusting device in such a way that it machines either one or otherworkpiece. Since the time required for changing workpieces is as a rulesubstantially shorter than the machining time, it is thus possible tokeep the workpiece in action practically constantly. Inactive times, asotherwise can occur if it is necessary to wait for other work spindlesor in a change of workpieces, can be averted.

While the work spindle is adjustable in the lateral direction along itstravel, the length of which spans both workpiece receptacles, it isadjustable in an additional direction perpendicular to the lateraldirection and to its axis of rotation. It is also adjustable in thedirection of its axis of rotation, to enable a positioning motion. Thesethree axes enable flexible machining of the workpieces.

All the NC axes (the X, Y, and Z axes, as well as the pivot axis S andadjusting axis V) serve the purpose of positioning in machining aworkpiece. Thus the workpiece is transported from the loading positionto the work position at the same time, so that no additional transportaxis or motions are required. If needed, however, an additionaltransport axis may be provided.

In an advantageous embodiment, at least two machining units areprovided, whose work spindles are for instance at a right angle from oneanother. Both machining units are adjustable in the lateral directionfar enough that they can machine both workpieces in alternation. Themachining units can either both work on the same workpiece or ondifferent workpieces. In conjunction with the possible pivoting of theworkpieces about the pivot axis, this enables a compensation of thepossibly variably long machining times for different sides. Forinstance, if machining the end face of the workpiece, which is oppositeits fastening face, is especially labor-intensive, then both themachining units can be used for that. While the first machining unit canmachine the first workpiece on its face end, the second machining unit,which is oriented differently, can machine the correspondingly pivotedother workpiece on its face end. If the machining of side faces is lesslabor-intensive, then this machining can for instance be performed by asingle machining unit, which to that end is moved suitably laterally toone or the other workpiece.

The advantages of the novel machine tool become especially apparent ifthe work spindles are provided with revolver heads or crown type turretheads. If the spindles present in these revolver heads and each carryingone tool are driven from the central work spindle, and if the onwardindexing of the crown type turret heads takes place while the spindlesare moving, then extremely short changing times, which are less than onesecond long, are achieved. Work can thus be done practicallyuninterruptedly. The high flexibility that the machine tool of theinvention offers in terms of dividing up the individual operations amongindividual machining units and tools, makes it possible here for theexisting work spindles to be utilized equally, so that the idle times ofthe machine can be kept quite low.

In a preferred embodiment, the two workpiece receptacles are disposedadjacent one another and side by side, and the pivot axis is orientedhorizontally. This has the advantage that the workpieces can each bechanged at the same height, and that a relatively flat machine frame canbe used, which can easily be designed to be rigid. This is favorable forthe machining precision.

The two machining units are preferably oriented in different directionsin space. For example, the first work spindle is disposed horizontallyand the second work spindle is disposed vertically. This makes itpossible for both machining units to work on the same workpiece at once.The machine tool can as a result be programmed quite flexibly, and it iseven possible for workpieces that require quite different machiningtimes on different sides to be machined without stopping or idly runningindividual work spindles. Furthermore, the work spindles can be movedpast one another without colliding with one another (for instance, thefirst work spindle can be moved from the first to the second workpieceand the second work spindle can be moved from the second to the firstworkpiece).

A height adjustment of the workpiece with respect to its workpiecereceptacle, or in other words an intended adjustment of the spacingbetween the center of the workpiece and the workpiece receptacle makesit possible, when differently fastened workpieces are being pivoted, fortheir respective centers to remain on the pivot axis. This not onlysimplifies programming of the machine tool but furthermore reduces thenecessary travel distances of the machining unit, which again reducesthe idle times.

If the workpiece receptacle moreover has a rotary positioning unit, bymeans of which the workpiece can be rotated about an adjusting axis atright angles to the pivot axis, then with the machine tool, even with asingle machining unit, genuine five-sided machining is possible. Forinstance, if a single horizontal work spindle is present, then with thetool the end face of the workpiece can be machined when it is in ahorizontal pivoted position, in which the adjusting axis is orientedhorizontally, and the side faces can be machined when the workpiece ispivoted such that the adjusting axis is oriented vertically. Thisadvantage becomes all the more important if at least two machining unitsare provided.

The machine tool of the invention is especially flexible if thepositioning units for pivoting the carriers of the workpiece receptaclesare positionable practically arbitrarily. In such a machine tool, it iseasily possible to make oblique bores, machine oblique faces, and thelike without requiring angled drilling heads or similar expensivecontrivances. In particular, the angles of the oblique bores or obliquefaces to the adjusting axis of the workpieces can be adjusted easily byprogramming the machine tool. Additional fixtures or the like (hardware)are unnecessary. The machining units upon each machining operationexecute merely a single positioning motion parallel to the axis ofrotation of the work spindles. This minimizes the effort and expense ofcontrol in comparison with guiding angled drilling heads, which requiresimultaneous adjustment of two axes in order to attain an advancingmotion. Practically any machining direction can be selected, which goesbeyond the conventional five-sided machining.

As needed, the machine tool can be constructed as a twin machine withtwo workpiece receptacles and one continuous machine frame. It is alsopossible to divide up the machine frame in terms of workpiecereceptacles such that individual units, each with one workpiecereceptacle, are obtained. These units can then be cascaded, so that byconnecting two units to one another a twin machine is obtained, and byconnecting three units to one another, a triplet machine is obtained.

If such a machine tool as described above is provided with, then theengineering expense is markedly less than for the design withcorrespondingly smaller machine tools, each with individual fasteningplaces. Once again, this makes for a cost saving.

Finally, conversion of existing machine tools is possible, by mountingdouble or multiple workpiece fastening places on existing fasteningplaces or carriers, optionally without planetary tables. The same istrue for the spindles, which can be doubled with suitable accessorydevices. Thus in the basic design, machine tools suitable even formachining relatively large, complicated workpieces, can be converted fortwin or multiple machining of smaller workpieces, and thus the partrejection rate can be double or multiplied further at little expense andwithout any loss of quality.

The individual workpiece fastening places can be connected with separaterotary positioning devices as needed. In a preferred embodiment,however, the rotary positioning devices have a common drive mechanism,and both fastening places are automatically moved in synchronizedfashion. The adjusting axes of the individual workpiece receptacledevices, as in a machine tool with single fastening places, arepreferably defined at right angles to the pivot axis of the carrier.

The machining units preferably have not merely a single pair of spindlesbut rather a revolver head equipped with a plurality of spindle pairs.Rotating the revolver head causes the spindles to change their positionin pairs; machining the two workpieces retained at adjacent fasteningplaces is therefore fully synchronized and has the same quality. Therevolver head, which has either twin spindles or four spindles perrevolver station, is preferably a crown type turret head. The spindlescan be supported in an attachment to be mounted on a conventional crowntype turret head; this makes it easier to convert machine tools from asingle spindle per station to double spindles or four spindles perstation.

In its preferred embodiment, the machine tool has two carriers and twomachining units, whose main axes or work spindles are perpendicular toone another. Here the advantages of a machine tool with single (notdouble) spindles and workpiece receptacles apply accordingly.

BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENTS

Further advantageous details will become apparent from the dependentclaims, the ensuing description, and the drawings. In the drawing, asingle exemplary embodiment of the invention is shown for purposes ofillustration. Shown are:

FIG. 1, the machine tool of the invention in a simplified perspectiveview, in which the outer machine covering has been shown transparent forthe sake of illustration;

FIG. 2, the machine tool of FIG. 1, on a different scale;

FIG. 2a, the machine tool of FIG. 2, in a different operating state;

FIG. 3, the machine tool of FIGS. 1 and 2, in the same work position, ina perspective view seen from a different direction;

FIG. 4, the machine tool of FIGS. 1 through 3, with machining units indifferent work positions, shown from a standpoint matching that of FIGS.1 and 2;

FIG. 4a, the machine tool of FIG. 4, in a different operating state,which differs from the operating state of FIG. 4 in terms of the pivotedpositions of the workpiece receptacles;

FIG. 4b, in a further operating state;

FIG. 5, the machine tool of FIGS. 1 through 4, with workpieces pivotedinto different machining positions;

FIG. 6, the drive mechanism of FIGS. 1 through 5, in the work positionseen in FIG. 5, from a different standpoint;

FIG. 7, another embodiment of the machine tool in a complete perspectiveview, in which the machine tool is shown schematically and partlytransparent, for the sake of illustration, with a tool carrier in theloading position;

FIG. 8, the machine tool of FIG. 7, in a schematic perspective view, andwith both tool carriers in the work position; and

FIG. 9, the machine tool of FIG. 7, in the work position of FIG. 1, in adifferent perspective view.

In FIG. 1, a machine tool 1 is shown, which has a work chamber 3enclosed by a housing 2. This work chamber is separated from itssurroundings, and control elements 4 that are required are disposedoutside the work chamber 3. On its front side, the housing 2 can beopened as needed by means of two swiveling or sliding doors 5, 6, togain access to the work chamber 3. In this chamber, there are twoworkpiece receptacles 8, 9 and work spindles 11, 12. The work spindles11, 12 belong to machining units 13, 14, which include suitable drivedevices for the work spindles 11, 12.

From the somewhat larger illustration in FIG. 2, it can be seen how theworkpiece receptacles 8, 9 and work spindles 11, 12 are disposed andembodied. The workpiece receptacle 8 has a U-shaped carrier 16, on whosecrosspiece 17, between two legs 18, 19 extending away from thecrosspiece 17, a workpiece receptacle device 21 is disposed. This deviceis provided with chucking means for detachably retaining a workpiece 22.The workpiece receptacle device 21 is also embodied such that it canrotate the workpiece 22 about an adjusting axis V, which extendsparallel to the legs 18, 19 and is perpendicular to the crosspiece 17.To that end, an adjusting device 23 is used, which is disposed betweenthe crosspiece 17 and the chucking device. The rotation about theadjusting axis V is shown in FIG. 2 on the right-hand side in terms ofan arrow P_(V) in conjunction with the workpiece receptacle 9.

The entire carrier 16 is pivotable about a pivot axis S. To that end,the legs 18, 19 of the carrier 16 are supported, on their ends remotefrom the crosspiece 17, on a machine frame 24, which to this end hasvertically-upward-extending columns 26, 27. A positioning unit 28, whichallows pivoting of the carrier 16 by at least 90 and preferably 180degrees or more is disposed in the column 26. The positioning unit isalso embodied such that it can define both the position shown in FIG. 2,in which the adjusting axis V is oriented horizontally, and some otherdefinable position. These positions are preferably finely graduated orcan be defined arbitrarily. To that end, the positioning unit isprovided with an NC axis. An alternative possibility is a positioningunit that is coupled with a serration, which defines discretepredetermined positions that are close together.

With respect to an imaginary vertical center plane between the workpiecereceptacle 8 and the workpiece receptacle 9, the workpiece receptacle 9is embodied mirror-symmetrically to the workpiece receptacle 8 andotherwise is identical to it. Without further reference and explanation,the reference numerals used in conjunction with the workpiece receptacle8 will also be used for the workpiece receptacle 9, provided with aprime for the sake of identification and distinction. The same is truefor the column 26 and the positioning unit 28. A fixed or movablepartition wall 10 is disposed between the workpiece receptacles 8, 9; inparticular, this prevents coolant and metal chips from passing theworkpiece receptacles 8, 9.

Neither the workpiece receptacle 8 nor the workpiece receptacle 9 isfixedly assigned to one of the machining units 13, 14. Instead, thesemachining units are provided equally for both workpiece receptacles 8,9. A guiding and adjusting device 30 to that end allows the targetedadjustment of the work spindles 11 in three directions in space X, Y, Zthat are structurally perpendicular to one another, and one of thesedirections in space coincides with the axis of rotation. To that end,the machining unit 13 is guided via a linear guide 31, whose guide rails32, 33 are schematically indicated in FIG. 2. The linear guide 32 ispart of an nc axis, which acts in the lateral direction X. Thisdirection is represented by an arrow X in FIG. 2 and is oriented to theparallel pivot axis S. The work spindle 11 of the machining unit 13 isadditionally adjustable in a direction Y perpendicular thereto, andtherefore there are again a corresponding linear guide and an NC axis.However, while the adjustment travel of the linear guide 31 in the Xdirection is so great that the work spindle can be brought both to theworkpiece 22 and to the workpiece 22′, the adjustment travel in the Ydirection is substantially shorter. Here, an adjustment travel thatcorresponds to the dimensions of the workpiece 22 suffices.

The machining unit 13 additionally has a further NC axis, by means ofwhich the work spindle 11 can be adjusted in the Z direction. The Zdirection is oriented perpendicular to the X direction and to the Ydirection and thus perpendicular to the pivot axis S. The Z directionforms the positioning direction for the work spindle 11.

On its end toward the workpiece 22, the work spindle 11 is provided witha revolver head 40, embodied as a crown type turret head. This revolverhas a plurality of spindles 41 through 46, whose axes of rotation aredisposed on an imaginary conical jacket. The revolver head 40 isrotatable into multiple work positions about an obliquely orientedindexing axis under program control via a system not further shown, andin each work position one of the spindles 41 through 46 is aligned withthe work spindle 11. All the spindles 41 through 46 are driven from thework spindle 11, and they travel with it regardless of the particularpivoted position. Each spindle 41 through 46 is provided with a chuckfor receiving a tool for metal-cutting machining of the workpiece 22.The tool located in a particular work position rotates about a verticalaxis of rotation, which coincides with the axis of the work spindle. Theother tools move past the workpiece 22 and thus run idly.

As seen particularly from FIG. 3, the work spindle 12 is also adjustableby means of three NC axes in the directions X, Y and Z, but in this casethe Y direction is the positioning direction. The work spindle 12 isoriented horizontally in the Y direction. Linear guides and axes of themachining unit 14 agree in principle with guides and axes of themachining unit 13 and thus are provided with the same referencenumerals. In other respects as well, the machining units 13, 14 arestructurally identical, and in particular the work spindle 12, on itsside toward the workpiece 22, is provided with a revolver head 40′,which matches the revolver head 40 of the machining unit 13, so that thedescription of the latter applies to it accordingly. To the extent thatthe elements of the machining unit 14 match those of the machining unit13, the same reference numerals are used, each with a prime todistinguish them. Each adjusting device 30, 30′ thus enables anadjustment of the respective work spindle 11, 12 in the lateraldirection X in an additional adjusting direction Y or Z and in apositioning direction Z or Y, respectively.

The mode of operation of the machine tool 1 described thus far is asfollows:

As an example, it is assumed that the workpiece receptacles 8, 9 of themachine tool 1 are first located in the pivoted position shown in FIG.1. The workpiece receptacle 9 has then been pivoted such that the crosspiece 17′ is located on the side of the pivot axis S pointing away fromthe door 6. The workpiece 22′ is accessible from the door 6. A change ofworkpieces can now be made, for instance, by removing the workpiece 22′,which has been completely machined previously, and introducing a newblank into the workpiece receptacle device 21′.

While the workpiece receptacle 9 is pivoted into a position suitable forthe change of workpieces, the workpiece receptacle 8 is in a workposition. In particular, both U-shaped carriers 16, 16′ are orientedwith their legs 18, 19, 18′, 19′ horizontally; the crosspiece 17 of theworkpiece receptacle 8 points toward the door 5. As seen particularlyfrom FIGS. 2 and 3, both machining units 13, 14 are at the workpiecereceptacle 8 that retains the workpiece 22. Because the work spindles11, 12 of the machining unit 13, 14 form a right angle with one another,they can both be active at the same time. For instance, with the tool ofthe spindle 42, a side face of the workpiece 22, which is shown merelyas an example as a cube, is machined while the tool of spindle 41′ ismachining the face end of this workpiece. The tool desired or requiredfor this is brought into the machining position by rotating theapplicable revolver head 40, 40′. The respective rotary motion isrepresented by arrows D in FIG. 3. The rotation of the revolver heads40, 40′ is effected without stopping the applicable work spindle 11, 12that drives all the spindles of the revolver head 40, 40′ synchronously.

By rotating the workpiece 22 about its adjusting axis V by means ofsuitable triggering of the adjusting device 23, a different side facecan be made to face upward and thus be machined by the machining unit13. In succession, all four sides of the workpiece 22 can thus bemachined. Intermediate positions can be set as needed as well.

The machine tool 1 permits uniform utilization of the machining units13, 14. For instance, if the workpiece 22 requires an approximatelyequal-length machining time for each of its five sides, and if themachining time of one side is equivalent to approximately that requiredfor the change of workpieces, then the workpiece receptacle 9 is pivotedout of the workpiece changing position, shown in FIGS. 1 through 3, intoa vertical position (FIG. 4b) in which the legs 18′, 19′ and thus theadjusting axis V of the workpiece 22′ extend in the vertical direction.The machining unit 14 is now moved in the X direction to the workpiecereceptacle 9, and a first side face of the workpiece 22′ can bemachined.

Once this has been done, and once the workpiece 22 has in the mean timebeen machined to completion, the workpiece receptacle 9 can be pivotedinto a horizontal position, as shown in FIG. 2a. (During this time, theworkpiece receptacle 8 can also be pivoted vertically, as in FIG. 4a.)In the horizontal position of the workpiece receptacle 9, the crosspiece17′ is retained on the side of the pivot axis S located at the door 6.While the machining unit 14 can now machine the end face of theworkpiece 22′, the machining unit 13 is brought over to the workpiece22′ and can machine the remaining three side faces in succession. Thusthree faces to be machined fall to the machining unit 13 to do, whilethe machining unit 14 has two faces to machine.

This applies accordingly for machining the workpiece 22 in the workpiecereceptacle 8. Once again, the machining of the end face and of the fourside faces can be distributed between the machining units 13, 14 in sucha way that both machining units 13, 14 are active practicallyconstantly. Idle times or time losses in which a work spindle 11 or 12is idling, while in the final analysis it waits for the other workspindle to finish its machining operation, can be minimized or evenomitted entirely. To further equalize the machining times, it is forinstance also possible for the machining unit 13 to machine three sidefaces at the machining unit 9 and for the workpiece receptacle 14 tomachine one side face and one end face, while for the workpiecereceptacle 8 the conditions are precisely the reverse. Thus via bothworkpieces 22, 22′, precisely five sides to be machined fall to eachmachining unit 13, 14.

Both workpiece receptacles 8, 9 can be pivoted independently of oneanother into arbitrary or nearly arbitrary positions. It can thus beassured that loading of a workpiece receptacle 8 or 9 does not impedethe work at the respective other workpiece receptacle 9 or 8. Incontrast to known circular indexing machine tools, in the machine tool 1the workpieces are not actually transported; that is there is no shiftin the location of the center of a respective workpiece 22, 22′.Instead, the machining units 13, 14 are moved between the workpiecereceptacles 8, 9. The motion of each workpiece 22, 22′ is limited to twosuperimposed rotary or pivoting motions, namely the pivoting motionabout the pivot axis S and the adjusting motion about the adjusting axisV. In both rotary or pivoting motions, the center of the respectiveworkpiece 22, 22′ remains essentially in place. The machining units 13,14, contrarily, execute only linear adjusting motions in three axis X,Y, Z. Only if needed can one additional pivot axis be provided for themachining units 13, 14.

The pivoting motion of the workpiece receptacles 8, 9, which is both atransporting and a positioning motion for the workpieces 22, 22′,enables not only the adjustment of various machining positions, but alsoan expedient way to remove chips. When the workpieces 22, 22′ arepivoted into different positions, chips that have been produced andcollected can drop downward or given a suitable speed can also beremoved by centrifugal motion.

Once the workpiece 22′ has been machined to completion, then from itsvertical position, for instance, it is pivoted back onto the door 6, asshown in FIG. 4, and the machining unit 14 is now moved laterally in theX direction to the workpiece receptacle 8 and the workpiece 22, in orderto perform machining operations there. The workpiece 22′ can now bechanged. Two enable access to the workpiece 22′, while machining isbeing done on the workpiece 22, the fixed or separately actuatable wall10 divides the work chamber 3 into half-chambers.

The machine tool 1 enables not only equal utilization of the machiningunits 13, 14 but furthermore very great flexibility in terms of themachining of the workpieces 22, 22′ from different directions in space.This can be seen particularly from FIGS. 5 and 6. Here, the machine tool1 is used to machine relatively complicated workpieces, which forinstance have oblique bores and/or oblique faces. The workpiecereceptacles 8, 9 are each pivoted into positions in which the verticalaxes V of the workpieces 22, 22′ form an acute angle with the vertical.Without the aid of oblique drilling heads or other means for angularadjustment of the tools retained in the spindles 42, 41′, oblique boresare attained in this way, and oblique faces can be milled.

Rotating the workpieces 22, 22′ about their respective adjusting axis Vby means of the adjusting device 23, 23′ makes it possible to define themachining directions practically arbitrarily. If curved or sphericalfaces are to be machined, it is moreover possible to adjust theworkpieces 22, 22′ in a targeted way while the respective tools are inengagement with the workpiece 22, 22′. The motions of the positioningunits 28, 28′ and of the adjusting units 23, 23′ are controlled,independently of one another, by the electronic control unit, notfurther shown, which is connected to the control elements 4. Thus makingoblique bores and machining oblique faces does not impede the overallcourse of the machining operations. If the machining unit 13 ismachining one side face from a direction perpendicular to it, forinstance, then the other machining unit 14 can be performing obliquemachining of the other workpiece.

If the machine tools are to be arranged for a different series ofworkpieces, then the workpiece receptacle devices 21, 21′ are adjustedto the new workpieces in such a way that their respective centers arelocated at least approximately on the pivot axis S. This is attained byadjusting the height, that is, the spacing from the pivot axis S, of thefastening plane, which is defined by the face of the workpiece 22, 22′opposite the face end.

In an extreme case, the machine tool 1 makes it possible to machinedifferent workpieces in the two workpiece receptacles 8, 9. Forinstance, the workpiece receptacle can be arranged for a first type ofworkpiece, and the workpiece receptacle 9 can be arranged for a secondtype of workpiece. If the requisite machining times of the differentsides of the two types of workpiece differ then a certain equalizationcan be attained here, because each machining unit 13, 14 serves bothworkpiece receptacles 8, 9, so that once again both machining units 13,14 are optimally utilized.

A machine tool 1 has at least one but preferably two machining units 13,14, which are assigned to two workpiece receptacles 8, 9. The machiningunits 13, 14 are adjustable in three axis X, Y, Z, and they can eachreach both workpiece receptacles 8, 9. The machining units 13, 14 areoriented such that their work spindles 11, 12 are at a preferably rightangle in space to one another. As a result, they can be moved past oneanother without colliding with one another. They can also both worksimultaneously on the same workplace. The workpiece receptacles can bepositioned independently of one another about a preferably common pivotaxis S, but this is not compulsory. The workpieces can also be rotatedabout an axis V that is perpendicular to the pivot axis. Thisdisposition enables flexible machining of the workpieces from arbitrarydirections in space. Because in principle each machining unit 13, 14 canmachine every side of the workpiece of each workpiece receptacle 8, 9,the two machining units 13, 14 can be utilized equally. This minimizesidle times and time losses.

In FIG. 7, a machine tool 100 is shown, which corresponds essentially tothe machine tool 1 shown in FIG. 1. It has a work chamber 103 enclosedby a housing 102. This work chamber is separated from its surroundings.Control elements 104 that are required are disposed outside the workchamber 103. The housing 102 can be opened on its front side over atleast half but preferably the entire width by means of two swiveling orsliding doors 105, 106. Two workpiece receptacles 108, 109 and workspindles 111, 112 are disposed in the work chamber 103. The workspindles 111, 112 belong to machining units 113, 114, which includecorresponding drive devices for the work spindles 111, 112. Theworkpiece receptacle 108 has a U-shaped carrier 116, whose cross piece117, between two legs 119 extending away from the cross piece 117,carries two workpiece receptacle devices 121 a, 121 b on its side towardthe inside of the carrier 116. Both workpiece receptacle devices 121 a,121 b are provided with respective chucking means for detachablyretaining workpieces 122 a, 122 b. The workpiece receptacle devices 121a, 121 b are disposed laterally side by side in a line that extendsparallel to the crosspiece 117 and intersects the two legs 118, 119.

Each of the workpiece receptacle devices 121 a, 121 b is provided with arotary positioning device 123 a, 123 b, by way of which the respectiveworkpiece 122 a, 122 b is rotatable either infinitely graduated form orin stages about an adjusting axis Va, Vb, which is perpendicular to thecrosspiece 117. The rotation about the adjusting axis Va or theadjusting axis Vb is represented by arrows Pv in FIG. 2. The workpieces122 a, 122 b can be fixed in set rotary positions.

The legs 118, 119, are supported on their respective free ends pivotablyabout a pivot axis S on a machine frame 124. For pivotable retention ofthe carrier 16, the machine frame has two parallel, verticallyupward-extending columns 126, 127. At least in or on the column 126,there is a positioning unit 128, which enables pivoting of the carrier116 by at least 90° and preferably 180° or more. The positioning device128 is also embodied such that it can define both fixedly predeterminedand preferably arbitrary intermediate positions. To that end, thepositioning unit 128 can be provided with an NC axis or can be coupledto a serration, which defines discrete, close-together positions.

With respect to an imaginary vertical center plane between the workpiecereceptacle 108 and the workpiece receptacle 109, the workpiecereceptacle 109 is embodied mirror-symmetrically to the workpiecereceptacle 108 and otherwise matches it. The description thereforeapplies accordingly, except that to distinguish them the referencenumerals of the individual parts of the workpiece receptacle 109 areprovided with a prime.

The machining units 113, 114 are not permanently assigned to either theworkpiece receptacle 108 or the workpiece receptacle 109. Instead, theycan be moved laterally such that they can be brought into workengagement with both the workpieces 122 a, 122 b of the workpiecereceptacle 108 and the workpieces 122 a′, 122 b′ of the workpiecereceptacle 109. This is accomplished by a guiding and adjusting device130, to allow a targeted lateral adjustment of the work spindle 111 inthree directions in space X, Y, Z at right angles to one another. Thespace direction X coincides with the pivot axis S. The space direction Zpreferably coincides with the axis of rotation of the work spindle 111.

To that end, the machining unit 113 is guided via a linear guide 131that belongs to the adjusting device 130 and has guide rails 132, 133.The linear guide 131 is actuated in the X direction by an NC axis. Acorresponding linear guide 134 an NC axis serve to adjust the machiningunit 113 in the Y direction. The adjustment travel in the X directionspans both workpiece receptacles 108, 109, while the adjustment travelin the Y or Z direction is markedly shorter.

The Z direction is also actuated via an NC axis 135 and serves as thepositioning direction. The work spindle 111 is embodied on its sidetoward the workpiece 122 a, 122 b as a crown type turret head, which hasa revolver head 140. The revolver head 140 has a total of ten pairs ofspindles 141 through 150 a, to each of which two spindles 141 a, 141 bthrough 150 a, 150 b belong. All the spindles 141 a through 150 b aredriven from the work spindle 111. The same is correspondingly true forthe spindles 141 a′ through 150 b′, which are driven from the workspindle 112. The spacings between two work spindles 141 a, 141 b through150 a, 150 b belonging to a spindle pair 141 through 150 all match thespacing between the adjusting axes Va, Vb of the workpiece receptacle108 and 109, respectively. Optionally, adjusting means may be providedon the workpiece receptacle 108, 109 for its fine adjustment. Thespindles 141 a, 141 b through 145 a, 145 b are disposed parallel to animaginary center line, which defines the primary direction of thespindle pair 141 through 145, and in the work position of the applicablespindles 141 a, 141 b through 150 b, 150 b is oriented in each caseparallel to the adjusting axis Va, Vb. The center lines are located onan imaginary cone with a relatively large opening angle. The otherspindle pairs 146 through 50 have center lines which are disposed on thejacket of a cone with a smaller opening. Thus in the circumferentialdirection of the revolver head 140, the spindle pairs 141 through 150are each disposed in alternation on the inner or the outer cone. Thisconstruction principle can also be employed for revolver heads that havesingle spindles or four spindles instead of the spindle pairs.

Tools are disposed on the spindles 141 a through 150 b, and the sametools are disposed at each two spindles belonging to a particularspindle pair 141 through 150.

The revolver heads 140, 140′ are structurally identical to one another,and so the description applies accordingly. Merely to distinguish them,the reference numerals for the revolver head 140′ are provided with aprime.

The mode of operation of the machine tool 100 described thus far is asfollows:

It is assumed that the machining units 113, 114 and the workpiecereceptacles 108, 109 of the machine tool 100 initially assume theposition shown in FIG. 1. Both machining units 113, 114 addressworkpieces disposed in the workpiece receptacle 108. The workpiecereceptacle 109 is accessible. The door 106 can be opened, and theworkpieces 122 a′, 122 b′ can be changed. To that end, the carrier 116′of the workpiece receptacle 109 is in the horizontal position; that is,its legs 118′, 119′ are horizontal. For changing workpieces, theworkpiece carrier 116′ can also be vertical.

The workpiece carrier 116 is located in a pivoted position suitable formachining of its workpieces 122 a, 122 b. This can for instance be thehorizontal position shown in FIG. 1. Both machining units 113, 114 canbe active. As soon as the change of workpieces at the workpiecereceptacle 108 has been completed, then as FIG. 2 shows one of themachining units, in the present case the machining unit 114, can bemoved to the workpiece receptacle 109. The machining of the workpieces122 a′, 122 b′ can now be done at the appropriate angle with the desiredtools. If needed, the machining unit 113 can be moved to the workpiecereceptacle 109 as well, so that only this machining unit, or bothmachining units 113, 114 work at the workpiece receptacle 109. In thiscase, the workpiece may be changed in receptacle 108. Rotating theworkpieces about the adjusting axis Va, Vb and by pivoting about thepivot axis S makes it possible to bring the workpieces 122 a, 122 b; 122a′, 122 b′ to their required machining positions, and genuine five-sidedmachining is possible with each machining station. The machining of theworkpieces 122 a, 122 b; 122 a′, 122 b′ is effected in synchronizedfashion by the spindles of the spindle pairs 141 through 150, so that inthe indexing time for one workpiece, two workpieces at a time arecompleted.

The change of whichever tool is active is done by rotating the revolverhead 140, 140′, putting the particular desired spindle pair in theactive position, in which the axes of rotation are aligned with the X orY axis, that is, the axes of the work spindles 111, 112. The rotation ofthe revolver head is effected with the work spindle 111, 112 running, orin other words with the spindles 141 a through 150 b in motion.

What is claimed is:
 1. A machine tool (1), in particular formetal-cutting machining of workpieces (22, 22′), comprising: at leasttwo devices (8, 9) for receiving workpieces, which devices each have atleast one carrier (16, 16′, 116, 116′), which is pivotable about a pivotaxis (S) and which is provided with a workpiece receptacle device (21,21′); wherein each carrier (16, 16′, 116, 116′) is assigned apositioning unit (23, 23′), by means of which the carrier (16, 16′) ispivotable about the pivot axis (S) to different positions and is fixablein a respective position; at least one first machining unit (13), whichhas at least one first work spindle (11), which can be driven to rotateabout an axis of rotation; a first guiding and adjusting device (30), bymeans of which the work spindle (11) is adjustable at least in apositioning direction (Z) that coincides with the axis of rotation andin a lateral direction (X) oriented parallel to the pivot axis (S);wherein the adjustment travel of the first guiding and adjusting device(30) in the lateral direction (X) parallel to the pivot axis (S) isdimensioned to be long enough that a tool, secured to said at least onefirst work spindle, can be brought selectively into engagement with theworkpieces (22, 22′) of the two workpiece receptacles (8, 9); andwherein the workpiece receptacle device (21, 21′, 121 a, 121 b) includesa rotary positioning device (23, 23′), by means of which the workpiece(22, 22′) can be adjusted purposefully about an adjusting axis (V),which is oriented perpendicular to the pivot axis (S) and intersects thepivot axis (S).
 2. A machine tool (1), in particular for metal-cuttingmachining of workpieces (22, 22′), comprising: at least two devices (8,9) for receiving workpieces, which devices each have at least onecarrier (16, 16′, 116, 116′), which is pivotable about a pivot axis (S)and which is provided with a workpiece receptacle device (21, 21′);wherein each carrier (16, 16′, 116, 116′) is assigned a positioning unit(23, 23′), by means of which the carrier (16, 16′) is pivotable aboutthe pivot axis (S) to different positions and is fixable in a respectiveposition; at least one first machining unit (13), which has at least onefirst work spindle (11), which can be driven to rotate about an axis ofrotation; a first guiding and adjusting device (30), by means of whichthe work spindle (11) is adjustable at least in a positioning direction(Z) that coincides with the axis of rotation and in a lateral direction(X) oriented parallel to the pivot axis (S); wherein the adjustmenttravel of the first guiding and adjusting device (30) in the lateraldirection (X) parallel to the pivot axis (S) is dimensioned to be longenough that a tool, secured to said at least one first work spindle, canbe brought selectively into engagement with the workpieces (22, 22′) ofthe two workpiece receptacles (8, 9); wherein each carrier 116, 116′ hastwo workpiece receptacle devices (121 a, 121 b); and wherein said atleast one first work spindle in the first machining unit comprises atleast one pair of spindles (141).
 3. The machine tool of claim 2,characterized in that the adjustment travel (X) of the first guiding andadjusting device (30) is oriented perpendicular to the positioningdirection (Z), and that the first work spindle (11) is adjustable bymeans of the first guiding and adjusting device (30) in an additionaladjusting direction (Y), which is oriented perpendicular to both thelateral direction (X) and the positioning direction (Z).
 4. The machinetool of claim 2, further comprising: at least one second machining unit(14), which has at least one second work spindle (12) which can bedriven to rotate about an axis of rotation; a second guiding andadjusting device (30′), by means of which the work spindle (12) isadjustable at least in a positioning direction (Y) that coincides withthe axis of rotation and in a lateral direction (X) oriented parallel tothe pivot axis (S); wherein the adjustment travel of the second guidingand adjusting device (30′) in the lateral direction (X) parallel to thepivot axis (S) is dimensioned to be long enough that a tool, secured tosaid at least one second work spindle, can be brought selectively intoengagement with both workpieces (22, 22′) of the two workpiecereceptacles (8, 9); wherein the adjustment travel (X) of the secondguiding and adjusting device (30′) is oriented perpendicular to thepositioning direction (Y), and the second work spindle (12) isadjustable by means of the second guiding and adjusting device (30′) inan additional adjusting direction (Z), which is oriented perpendicularto both the lateral direction (X) and the positioning direction (Y). 5.The machine tool of claim 4, characterized in that each of said firstand second work spindles (11, 12) is provided with a respective revolver(40, 40′), which has a plurality of driven spindles (41, 42, 43, 44, 45,46; 41′, 42′, 43′, 44′, 45′, 46), which each carry separate tools, andrespective axes of rotation of said first and second work spindles (11,12) are oriented in different directions perpendicular to one another.6. A machine tool (1), in particular for metal cutting machining ofworkpieces (22, 22′), comprising: at least two devices (8, 9) forreceiving workpieces, which devices each have at least one carrier (16,16′, 116, 116′), which is pivotable about a pivot axis (S) and which isprovided with a workpiece receptacle device (21, 21′); wherein eachcarrier (16, 16′, 116, 116′) is assigned a positioning unit (23, 23′),by means of which the carrier (16, 16′) is pivotable about the pivotaxis (S) to different positions and is fixable in a respective position;at least one first machining unit (13), which has at least one firstwork spindle (11), which can be driven to rotate about an axis ofrotation; a first guiding and adjusting device (30), by means of whichthe work spindle (11) is adjustable at least in a positioning direction(Z) that coincides with the axis of rotation and in a lateral direction(X) oriented parallel to the pivot axis (S); wherein the adjustmenttravel of the first guiding and adjusting device (30) in the lateraldirection (X) parallel to the pivot axis (S) is dimensioned to be longenough that a tool, secured to said at least one first spindle, can bebrought selectively into engagement with the workpieces (22, 22′) of thetwo workpiece receptacles (8, 9); and wherein the carriers (16, 16′) ofthe workpiece receptacle (8, 9) are embodied in the shape of a U and aredisposed side by side and have two legs (18, 19; 18′, 19′) joinedtogether at ends thereof via respective crosspieces (17, 17′), on whichthe workpiece receptacle device (21, 21′) is disposed; and that the endsof the legs (18, 19; 18′, 19′) remote from the crosspiece (17, 17′) areconnected to a positioning unit (28, 28′) that defines the pivot axis(S), and the pivot axes (S) of the two carriers (16, 16′) coincide. 7.The machine tool of claim 1, characterized in that the rotarypositioning devices (123 a, 123 b) are actuatable synchronously with oneanother.
 8. The machine tool of claim 7, characterized in that therotary positioning devices (123 a, 123 b) have a common drive mechanism.9. The machine tool of claim 2, characterized in that the rotarypositioning devices (123 a, 123 b) are actuatable synchronously with oneanother.
 10. The machine tool of claim 9, characterized in that therotary positioning devices (123 a, 123 b) have a common drive mechanism.11. The machine tool of claim 2, characterized in that spindles (141 athrough 150 b) of each said spindle pair (141 through 150) are driven insynchronized fashion, and the spindles (141 a, 141 b; 141′a, 141′b) ofeach said spindle pair (141, 141′) have a common drive source (111,112).
 12. The machine tool of claim 2, characterized in that said atleast one pair of spindles in the first machining unit comprises aplurality of spindles (141 a, 141 b; 141 a′, 141 b′) that are providedin pairs, each pair on one revolver (140, 140′) which has a plurality ofdriven spindles (141 a through 150 b; 141 a′ through 150 b′), which eachcarry separate tools, wherein spindles (141 a, 150 b) of the spindlepairs (141) through (150) are each disposed parallel to a center linewhich is located centrally between them and on a jacket of an imaginarycone.
 13. The machine tool of claim 12, characterized in that thespindles (141 a through 150 b) of the spindle pairs (141 through 150)are each disposed parallel to a center line located centrally betweenthem, which line is located in alternation on the jacket of an imaginarycone having a larger opening angle and of an imaginary cone having asmaller opening angle.
 14. The machine tool of claim 6, furthercomprising: at least one second machining unit (14), which has at leastone second work spindle (12) which can be driven to rotate about an axisof rotation; a second guiding and adjusting device (30′), by means ofwhich the work spindle (12) is adjustable at least in a positioningdirection (Y) that coincides with the axis of rotation and in a lateraldirection (X) oriented parallel to the pivot axis (S); wherein theadjustment travel of the second guiding and adjusting device (30′) inthe lateral direction (X) parallel to the pivot axis (S) is dimensionedto be long enough that a tool, secured to said at least one second workspindle, can be brought selectively into engagement with both workpieces(22, 22′) of the two workpiece receptacles (8, 9); wherein theadjustment travel (X) of the second guiding and adjusting device (30′)is oriented perpendicular to the positioning direction (Y), and thesecond work spindle (12) is adjustable by means of the second guidingand adjusting device (30′) in an additional adjusting direction (Z),which is oriented perpendicular to both the lateral direction (X) andthe positioning direction (Y).
 15. The machine tool of claim 6,characterized in that said at least one pair of spindles in the firstmachining unit comprises a plurality of spindles (141 a, 141 b; 141 a′,141 b′) that are provided in pairs, each pair on one revolver (140,140′) which has a plurality of driven spindles (141 a through 150 b; 141a′ through 150 b′), which each carry separate tools, wherein spindles(141 a, 150 b) of the spindle pairs (141) through (150) are eachdisposed parallel to a center line which is located centrally betweenthem and on a jacket of an imaginary cone.
 16. The machine tool of claim6, characterized in that the adjustment travel (X) of the first guidingand adjusting device (30) is oriented perpendicular to the positioningdirection (Z), and that the first work spindle (11) is adjustable bymeans of the first guiding and adjusting device (30) in an additionaladjusting direction (Y), which is oriented perpendicular to both thelateral direction (X) and the positioning direction (Z).
 17. The machinetool of claim 6, further comprising: at least one second machining unit(14), which has at least one second work spindle (12) which can bedriven to rotate about an axis of rotation; a second guiding andadjusting device (30′), by means of which the work spindle (12) isadjustable at least in a positioning direction (Y) that coincides withthe axis of rotation and in a lateral direction (X) oriented parallel tothe pivot axis (S); wherein the adjustment travel of the second guidingand adjusting device (30′) in the lateral direction (X) parallel to thepivot axis (S) is dimensioned to be long enough that a tool, secured tosaid at least one second work spindle, can be brought selectively intoengagement with both workpieces (22, 22′) of the two workpiecereceptacles (8, 9); wherein the adjustment travel (X) of the secondguiding and adjusting device (30′) is oriented perpendicular to thepositioning direction (Y), and the second work spindle (12) isadjustable by means of the second guiding and adjusting device (30′) inan additional adjusting direction (Z), which is oriented perpendicularto both the lateral direction (X) and the positioning direction (Y). 18.The machine tool of claim 6, characterized in that each of said firstand second work spindles (11, 12) is provided with a respective revolver(40, 40′), which has a plurality of driven spindles (41, 42, 43, 44, 45,46; 41′, 42′, 43′, 44′, 45′, 46), which each carry separate tools, andrespective axes of rotation of said first and second work spindles (11,12) are oriented in different directions perpendicular to one another.19. The machine tool of claim 6, characterized in that the rotarypositioning devices (123 a, 123 b) are actuatable synchronously with oneanother.
 20. The machine tool of claim 19, characterized in that therotary positioning devices (123 a, 123 b) have a common drive mechanism.21. The machine tool of claim 6, characterized in that spindles (141 athrough 150 b) of each said spindle pair (141 through 150) are driven insynchronized fashion, and the spindles (141 a, 141 b; 141′a, 141′b) ofeach said spindle pair (141, 141′) preferably have a common drive source(111, 112).
 22. The machine tool of claim 6, characterized in that saidat least one pair of spindles comprises a plurality of spindles in thefirst machining unit (141 a, 141 b; 141 a′, 141 b′) that are provided inpairs, each pair on one revolver (140, 140′) which has a plurality ofdriven spindles (141 a through 150 b; 141 a′ through 150 b′), which eachcarry separate tools, wherein spindles (141 a, 150 b) of the spindlepairs (141) through (150) are each disposed parallel to a center linewhich is located centrally between them and on a jacket of an imaginarycone.
 23. The machine tool of claim 22, characterized in that thespindles (141 a through 150 b) of the spindle pairs (141 through 150)are each disposed parallel to a center line located centrally betweenthem, which line is located in alternation on the jacket of an imaginarycone having a larger opening angle and of an imaginary cone having asmaller opening angle.
 24. The machine tool of claim 1, characterized inthat the adjustment travel (X) of the first guiding and adjusting device(30) is oriented perpendicular to the positioning direction (Z), andthat the first work spindle (11) is adjustable by means of the firstguiding and adjusting device (30) in an additional adjusting direction(Y), which is oriented perpendicular to both the lateral direction (X)and the positioning direction (Z).
 25. The machine tool of claim 1,further comprising: at least one second machining unit (14), which hasat least one second work spindle (12) which can be driven to rotateabout an axis of rotation; a second guiding and adjusting device (30′),by mean s of which the work spindle (12) is adjustable at least in apositioning direction (Y) that coincides with the axis of rotation andin a lateral direction (X) oriented parallel to the pivot axis (S);wherein the adjustment travel of the second guiding and adjusting device(30′) in the lateral direction (X) parallel to the pivot axis (S) isdimensioned to be long enough that a tool, secured to said at least onesecond work spindle, can be brought selectively into engagement withboth workpieces (22, 22′) of the two workpiece receptacles (8, 9);wherein the adjustment travel (X) of the second guiding and adjustingdevice (30′) is oriented perpendicular to the positioning direction (Y),and the second work spindle (12) is adjustable by means of the secondguiding and adjusting device (30′) in an additional adjusting direction(Z), which is oriented perpendicular to both the lateral direction (X)and the positioning direction (Y).
 26. The machine tool of claim 25,characterized in that each of said first and second work spindles (11,12) is provided with a respective revolver (40, 40′), which has aplurality of driven spindles (41, 42, 43, 44, 45, 46; 41′, 42′, 43′,44′, 45′, 46), which each carry separate tools, and respective axes ofrotation of said first and second work spindles (11, 12) are oriented indifferent directions perpendicular to one another.
 27. The machine toolof claim 1, characterized in that spindles (141 a through 150 b) of eachsaid spindle pair (141 through 150) are driven in synchronized fashion,and the spindles (141 a, 141 b; 141′a, 141′b) of each said spindle pair(141, 141′) preferably have a common drive source (111, 112).
 28. Themachine tool of claim 15, characterized in that spindles (141 a through150 b) of said spindle pairs (141 through 150) are each disposedparallel to a center line located centrally between them, which line islocated in alternation on the jacket of an imaginary cone having alarger opening angle and of an imaginary cone having a smaller openingangle.